es-toolkit/docs/reference/array/intersection.md

intersection

Returns the intersection of two arrays.

This function takes two arrays and returns a new array containing the elements that are present in both arrays. It effectively filters out any elements from the first array that are not found in the second array.

Signature

function intersection<T>(firstArr: T[], secondArr: T[]): T[];

Parameters

• firstArr (T[]): The first array to compare.
• secondArr (T[]): The second array to compare.

Returns

(T[]) A new array containing the elements that are present in both arrays.

Examples

const array1 = [1, 2, 3, 4, 5];
const array2 = [3, 4, 5, 6, 7];
const result = intersection(array1, array2);
// result will be [3, 4, 5] since these elements are in both arrays.

Lodash Compatibility

Import intersection from es-toolkit/compat for full compatibility with lodash.

• intersection can accept multiple array-like objects to find common elements.
• intersection returns only unique elements

import { intersection } from 'es-toolkit/compat';

const array1 = [1, 2, 3, 4, 4, 5];
const array2 = [2, 4];
const array3 = [4, 6];
const result = intersection(array1, array2, array3);
// The result is [4] because this only element is present in every array.

const arrayLike1 = { 0: 1, 1: 2, 2: 3, length: 3 };
const arrayLike2 = { 0: 2, 1: 3, length: 2 };
const result2 = intersection(arrayLike1, arrayLike2);
// The result2 is [2, 3] because these elements are present in both array-like objects.